I, personally, don't smoke around children in confined areas. Does this mean I would actually vote for a law that enters someone's private property and disallows legal acts? NO NO NO. If you think a law destroying private property rights is going to somehow increase children's health, or make "abusive" parents "good", I would argue that you are sadly mistaken.
It will either occur by legislation or by the courts. My guess is the courts will kick it off.